SpeedRacer's Dyno Chart

Message

Happyboy · #21 Post by **Happyboy** » Sun May 10, 2009 4:48 am

No, i don't mistake ignition timing for valve timing.

You are shortening or lengthing the overlap time the intake and exhaust valves are open at the same time. What this is also doing is adjusting the distance the valves are away from the piston. By going a larger exhaust time you are holding the valve open longer which increases the chance the piston will nail that valve if it floats. Hence me saying i usually play it safe cause i like motors that don't go boom. I am scared and cheap like that.

I will though, be messing with the timing more on my next adjustment....those numbers rock!

thedeatons · #22 Post by **thedeatons** » Sun May 10, 2009 5:28 am

Okay, I understand your position now.

We also reduce the rev limiter to 10k and run the stock dual valve springs for peace of mind....

cannondale27 · #23 Post by **cannondale27** » Sun May 10, 2009 2:55 pm

Porting also has changed in last two years quite a bit. For a 467 thats normal hp.

thedeatons · #24 Post by **thedeatons** » Mon May 11, 2009 3:32 am

This was actually OLD Timbo porting, Tim said he did it back when he first started experimenting with cam timing. Cory Jenkins old engine.

TricityCdale · #25 Post by **TricityCdale** » Tue May 12, 2009 4:04 pm

OK, so for clarification, was this a 450cc engine or a 467cc?

speedracer · #26 Post by **speedracer** » Tue May 12, 2009 9:58 pm

Its a 467.It is confusing,LOL.

thedeatons · #27 Post by **thedeatons** » Wed May 13, 2009 2:58 am

Why would you even ask that?

Just kidding.... LOL.... I will try to edit that first post...

James

Gibson265R · #28 Post by **Gibson265R** » Wed May 27, 2009 3:35 am

My 2 cents...dynos do vary...I attended MMI (i didnt learn much more than how to run dynos)...we had a class on engine performance that had 2 seperate dynos and if you were to run the same bike on one you could have a 8 hp increase if you just moved to the other dyno...maybe this was just some kind of mis-calibration on the schools part. Maybe AFR is really the only thing that really matters....the straighter the line the better....i did notice that some engines like to go slightly leaner in the upper RPM ranges to produce higher peak HP numbers....we also learned how to degree cams, among other things, but never tested adjusted cam timing on the dyno.

wistech · #29 Post by **wistech** » Thu Jul 16, 2009 3:16 pm

QUOTE (Happyboy @ May 8 2009, 10:24 PM) <{POST_SNAPBACK}>

ok, these dyno numbers have been buggin me for a long while. What gives on the numbers getting bigger on setups that haven't changed in a year? Is it the cam timing? I would have thought this was at ~50hp maybe 52 max, but you got 56??!!

Or, is it the dyno? Maybe Little Sahara OK is just a stingy dyno. :/

A couple years ago these were the standard numbers we were getting with our 467's. Since the unavailabilty of stroker cranks we put the focus on stock strokes to get similar hp-torque charts and sometimes even better than the strokers. Of course its a bit of a hassle with higher compresion,dual exhaust ,crazy cam timing .

speedracer · #30 Post by **speedracer** » Sat Jul 18, 2009 3:16 am

Wistech,how much more is gained by running duals?I see the stock stroke machines are making great numbers.